Help With 2 Questions, Please

My DIL is graduating from nursing school and I want to make her of of the typical "scrubs shirt" cakes with all of the accoutrements of the profession. I've already made the gumpaste decorations, but here are my questions:

1. I'm starting with a half-sheet pan. Should I carve it to get the "sleeves" or should the sleeves be extra pieces of cake added on. It seems like I would lose a lot of cake if I carve.

2. I've only covered a few cakes with fondant, and then only round ones. I'm not that good at it yet. I've never covered an odd-shaped cake. Any tips or suggestions that would make it easier? I've watched video tutorials of covering a square cake but can't find one for odd shapes.

Thanks so much for your replies. DeliciousDesserts, those were some really helpful suggestions! Why should I be patient? You guys should be sitting at your computers waiting to come to my aid at all times! hahaha! Just joking! Sorry I got antsy.